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This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The Object.entries()
method returns an array of a given object's own enumerable property [key, value]
pairs, in the same order as that provided by a for...in
loop (the difference being that a for-in loop enumerates properties in the prototype chain as well).
Syntax
Object.entries(obj)
Parameters
obj
- The object whose enumerable own property
[key, value]
pairs are to be returned.
Return value
An array of the given object's own enumerable property [key, value]
pairs.
Description
Object.entries()
returns an array whose elements are arrays corresponding to the enumerable property [key, value]
pairs found directly upon object
. The ordering of the properties is the same as that given by looping over the property values of the object manually.
Examples
var obj = { foo: "bar", baz: 42 }; console.log(Object.entries(obj)); // [ ['foo', 'bar'], ['baz', 42] ] // array like object var obj = { 0: 'a', 1: 'b', 2: 'c' }; console.log(Object.entries(obj)); // [ ['0', 'a'], ['1', 'b'], ['2', 'c'] ] // array like object with random key ordering var an_obj = { 100: 'a', 2: 'b', 7: 'c' }; console.log(Object.entries(an_obj)); // [ ['2', 'b'], ['7', 'c'], ['100', 'a'] ] // getFoo is property which isn't enumerable var my_obj = Object.create({}, { getFoo: { value: function() { return this.foo; } } }); my_obj.foo = "bar"; console.log(Object.entries(my_obj)); // [ ['foo', 'bar'] ] // non-object argument will be coerced to an object console.log(Object.entries("foo")); // [ ['0', 'f'], ['1', 'o'], ['2', 'o'] ]
Converting an Object
to a Map
The new Map()
constructor accepts an iterable of entries
. With Object.entries
, you can easily convert from Object
to Map
:
var obj = { foo: "bar", baz: 42 }; var map = new Map(Object.entries(obj)); console.log(map); // Map { foo: "bar", baz: 42 }
Polyfill
To add compatible Object.entries
support in older environments that do not natively support it, you can find a Polyfill in the tc39/proposal-object-values-entries or in the es-shims/Object.entries repositories.
Specifications
Specification | Status | Comment |
---|---|---|
ECMAScript 2017 Draft (ECMA-262) The definition of 'Object.entries' in that specification. |
Draft | Initial definition. |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|
Basic support | 51.0 [1] | 47 (47) | No support | No support | No support [2] |
Feature | Android | Android Webview | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile | Chrome for Android |
---|---|---|---|---|---|---|---|
Basic support | No support | 51.0 [1] | 47.0 (47) | No support | No support | No support | 51.0 [1] |
[1] Behind a flag.
[2] See bug 150131.